I easily opened the macbook air, and followed the procedure. Nothing looks wrong, the cable looks normal, I don't see any particular trace of oxydation, everything was apparently properly plugged. I don't think the picture attached can help... nevertheless, just in case...

Shaking the cables and plugs did not help so far... does it mean that the dramatic scenario is the likely to have happened (display failure?). Any other suggestion?

1 Answer

You'll need a flashlight to shine though the back side of the lid (Apple Logo) are you able to see the faint images of your icon's on your desktop? If you do then only the backlight is gone which also explains why the diagnostics didn't see it as a fault.

You'll need to test the logic board, do you have the needed tools and skill's?

Update (05/01/2017)

You've isolated the fault down to the displays ribbon cable and/or the logic board connector as the most likely fault.

Follow this IFIXIT guide: MacBook Air 11" Mid 2012 Display Assembly Replacement. Start off doing the first three steps (1 - 3), then jump down to Step19. Inspect the internal displays connection do you see any corrosion or is the connection not fully secured? Disconnect and carefully lift the cable does the cable look damaged in any way?

If you see something take a picture so we can see and post it in a fresh answer.

It will see major failings but when you start looking into input & output devices it gets tricky! No all of them have a means to diagnostically communicate.

Think of it this way how would you test a light switch running software or physically taking a Volt/Ohm meter to test the circuit?

I like the terms inner-world and outer-world when talking about digital devices. Software diagnostics can only test inner-world functions, it can't test outer-world interfaces. Or, output only devices like displays.

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